The manufacture of an aircraft involves the complex assembly of many mechanical and electronic components, each of which must accurately and reliably function in coordination with other components to ensure a safe and reliable aircraft. Individual components are put through stringent testing before assembly, but must be further tested after assembly to ensure continued functionality and proper interconnection by wiring harnesses and/or pneumatic and hydraulic lines. It is also necessary to keep a permanent record of the tests performed on an aircraft during assembly, as mandated by federal quality control regulations and as required by aircraft manufacturers to facilitate later maintenance and failure analysis.
One of the systems embodied in any aircraft that must be tested during assembly is the flight controls system. The flight controls system comprises the various control surfaces disposed in the aircraft's wings, elevator, and tail that provide for control of the aircraft's altitude and direction. Coacting with these surfaces are cockpit controls, aircraft computers, drive motors, position sensing transducers, and "line replaceable units" that operate to control, monitor, and report the configuration or status of control surfaces. The components of the flight controls system are typically tested individually as they are installed onto the aircraft, and may later be tested contemporaneously with subsequently installed interdependent components and during subsequent maintenance of the aircraft.
Conventional methods for testing aircraft flight controls systems, as well as other aircraft systems, have depended heavily on manual manipulation of the aircraft controls and recording of test data by operators. Typically, to test any particular component of the aircraft over its complete service range while the aircraft is on the ground, the operator must manually position various control surfaces and set cockpit circuit breakers to simulate in-flight conditions such as altitude and air speed. The operator then takes portable test instruments to the point of the aircraft at which the component under test is located, and breaks into the aircraft wiring with test probes to monitor performance of that particular component. The resulting data is manually recorded for future reference. This process must be repeated for each component that is to be tested, consuming great time and expense and providing numerous opportunities for operator error.
More recently developed conventional aircraft test systems are semi-automated in an attempt to reduce the manual steps that must be performed by an operator. These semi-automated systems may rely on built-in test equipment (BITE) routines contained within individual line replaceable units (LRUs) embodied in the flight controls system. However, such systems are limited by their dependence on mechanical simulation of in-flight conditions through manual circuit breaker settings, manual positioning of cockpit controls and control surfaces, and the manual transcription of test data necessary to produce a quality control paper record of the test results for archiving.
An example of a conventional semi-automated aircraft test system is taught by U.S. Pat. No. 4,626,996 to Arlott. The semi-automated test system disclosed uses a master computer that communicates with an onboard flight computer and onboard transducers. However, the test system disclosed is also heavily dependent on a number of remote data acquisition units that include microprocessors and associated memory, and remote transducers that must be mounted on the various aircraft components to be tested. The system is further limited in that it does not provide for automated, electronic simulation of in-flight conditions during ground testing of the aircraft, but actually tests the aircraft systems while the aircraft is airborne.